Field of the Invention
The present invention relates to an organic light emitting diode display device including a built-in touch panel, and more particularly, to an organic light emitting diode display device including a built-in touch panel in which a connection defect between the touch panel and an organic light emitting diode array may be prevented and a bezel region may be reduced.
Discussion of the Related Art
Recently, organic light emitting diode (OLED) display devices have received attention as next generation display devices. OLED display devices are self-emissive devices in which light is emitted from an organic emission layer due to recombination of electrons and holes. The OLED display devices have high luminance and low driving voltage, and may be manufactured to have an ultra-thin thickness. Also, demand for the addition, to such an OLED display device, of a touch panel for transmitting separate information by touching a portion of the touch panel with a hand or a separate input member is increasing.
In general, touch panels are classified into three types: an Add-On type, an On-Cell type, and an In-Cell type. The Add-On type touch panel is attached to an outer surface of the OLED display device. The On-Cell type touch panel is deposited on the OLED display device. And, the In-Cell type touch panel is formed inside the OLED display device.
Because the In-Cell type touch panel is integrated into an OLED display device, the thickness of the OLED display device having the built-in In-Cell type touch panel is smaller than that of an OLED display device having a built-in Add-On type or On-Cell type touch panel.
FIG. 1A is a plan view of an OLED display device including a built-in touch panel according to the related art. FIG. 1B is a sectional view taken along line I-I′ of FIG. 1A.
As shown in FIGS. 1A and 1B, an OLED display device including a built-in touch panel according to the related art includes a lower substrate 10 with an OLED array 11 formed thereon, an upper substrate 20 with a touch panel 16 formed thereon, and an adhesive agent 12 that adheres the upper substrate 20 to the lower substrate 10. In this regard, a touch signal applied to the touch panel 16 is applied to the OLED array 11 via a conductive ball 15b contained in a sealant 15a. 
On the lower substrate 10 is formed the OLED array 11 including thin film transistors (TFTs) and OLEDs respectively connected to the TFTs. The OLED array 11 includes a lower connection pad 14a for receiving signals applied to the touch panel 16.
At one side of the lower substrate 10 is formed a drive IC 13a, and the drive IC 13a is connected to a flexible printed circuit board (FPCB) 13b. The FPCB 13b includes a timing control unit (not shown) for supplying various control signals to drive the OLED array 11, a power supply (not shown) for supplying a driving voltage, and the like. In addition, a signal of the FPCB 13b is applied to the OLED array 11 via the drive IC 13a. 
On the upper substrate 20 is formed the touch panel 16 including first and second sensor electrodes (not shown), routing lines (not shown) connected to the first and second sensor electrodes (not shown), and upper connection pads 14b connected to ends of the routing lines (not shown). The conductive balls 15b contained in the sealant 15a are disposed between the upper connection pads 14b and the lower connection pads 14a. 
In the related art OLED display devices having a built-in touch panel, a space for connecting the upper connection pad 14b to the lower connection pad 14a is, however, needed. Accordingly, a width W of the bezel region increases, which then reduces the display area.
Moreover, the lower substrate 10 with the OLED array 11 formed thereon generally has a greater area than that of the upper substrate 20 with the touch panel 16 formed thereon, and thus, the upper connection pad 14b, the lower connection pad 14a, and the sealant 15a are exposed to the outside. Accordingly, contact properties between the sealant 15a and the upper connection pad 14b and between the sealant 15a and the lower connection pad 14a are degraded.
FIGS. 2A to 2C are images showing defects of the related art OLED display device having a built-in touch panel.
As described above, when the upper connection pad 14b, the lower connection pad 14a, and the sealant 15a are exposed to the outside, external moisture may permeate into the exposed region, and the conductive ball 15b and the sealant 15a may be separated from each other by external stress. Accordingly, disconnection of the routing lines occurs, as shown in FIG. 2A, or the upper and lower connection pads 14b and 14a are separated from the sealant 15a, as shown in FIG. 2B. Thus contact properties between the sealant 15a and the upper connection pad 14b and between the sealant 15a and the lower connection pad 14a are degraded. In addition, as shown in FIG. 2C, a crack is formed at the upper connection pad 14b and thus external moisture and oxygen permeate into the OLED display device via the crack, which results in deteriorated reliability of the OLED display device.